Investigators said the Antonov An-148 plane crashed in the Ramensky district on the outskirts of Moscow at 2:48 pm (1128 GMT) after taking off from the capital's Domodedovo airport.

"Sixty-five passengers and six crew members were on board, and all of them died," Russia's office of transport investigations said in a statement.

The flight was operated by the domestic Saratov Airlines and was headed for Orsk, a city in the Ural mountains.

President Vladimir Putin offered "his profound condolences to those who lost their relatives in the crash," his spokesman Dmitry Peskov said.

- Snowbound crash site -

The crash site was enveloped in heavy snow, making it difficult to access, with emergency workers forced to park their vehicles and access the wreckage by foot.

Russia has experienced record snowfall in recent weeks and investigators said they would not rule out poor weather as a possible cause of the disaster.

A regional official said the aircraft's black box had been retrieved.

The Russian-made plane was reportedly seven years old and bought by Saratov Airlines from another Russian airline a year ago.

- Putin orders probe -

Emergency services said in a statement that more than 150 rescue workers were deployed to the site.

The transport investigations office said the plane disappeared from radar screens around four minutes after take-off.

The Russian transport minister was on his way to the crash site, agencies reported. The transport ministry said several causes for the crash were being considered, including weather conditions and human error.

Peskov said Putin had ordered the establishment of a special commission to probe the crash.

The governor of the Orenburg region, where the plane was flying to, told Russian media that "more than 60 people" on board the plane were from the region.

Prosecutors opened an investigation into Saratov Airlines following the crash. Russia's Investigative Committee will consider all possible causes, RIA Novosti news agency reported.

Saratov Airlines was founded in the 1930s and flies to 35 Russian cities. Its hub is Saratov Central Airport in southern Russia.

- Grieving relatives -

Local media website Ural56.ru in the Orenburg region showed footage of distressed relatives at Orsk airport, where the plane was due to land.

Andrei Odintsov, the mayor of the city of Orsk, told Russian state television that six psychologists and four ambulances with medics were working with the relatives in the small airport.

Orsk is the second biggest city in the Orenburg region, near Russia's border with Kazakhstan.